GDNF gene therapy attenuates retinal ischemic injuries in rats

[摘要] Purpose: To examine the protective effects of glial cellline-derived neurotrophic factor (GDNF) on retinal ischemia-reperfusioninjury by using gene delivery.Methods: Gene delivery to retinal cells was achieved throughintravitreal injections of recombinant adeno-associated virus expressingGDNF (rAAV-GDNF) in the right eyes and AAV expressing Escherichia coliLacZ (rAAV-LacZ) in the left eyes of Sprague-Dawley rats. Ischemicinjury was introduced three weeks after gene delivery. The synthesis andaccumulation of GDNF within the retina were determined usingimmunohistochemistry and enzyme-linked immunosorbent assay (ELISA) threeweeks after gene delivery. The neuroprotective effects of GDNF wereevaluated by determining the preservation of the inner retina thicknessand the cell counts in the retinal ganglion cell (RGC) layer one weekafter reperfusion. In addition, eletroretinograms (ERGs) were performedto determine the functionality of the retinas. Finally, the levels ofRGC apoptosis were measured using the TdT-dUTP terminal nick-endlabeling (TUNEL) method 6 h after reperfusion.Results: Gene expression of GDNF was demonstrated throughimmunohistochemistry and ELISA. Thinning of the inner retina anddecreased numbers of cells in RGC layer were noted after ischemia in allof the eyes. However, the thickness of the inner retina and the numbersof cells in RGC layer were better preserved in rAAV-GDNF treated eyesthan in rAAV-LacZ treated eyes seven days after reperfusion (p=0.028 andp<0.001, respectively). Also, seven days after reperfusion, therAAV-GDNF treated eyes had retained larger b-wave amplitudes thanrAAV-LacZ treated eyes (p=0.003). Finally, rAAV-GDNF treated eyes hadstatistically fewer apoptotic cells in the RGC layer than the controleyes (p=0.011).Conclusions: In these experiments, GDNF moderately protected ratretina from ischemia-reperfusion injury, possibly by preventingapoptosis in retinal cells.

[学科分类] 生物化学/生物物理